LNG World Shipping

Keeping LNG carriers ship-shape in the frozen north

The world’s newest exporter, Yamal LNG is also one of the most remote production plants. The 15 icebreaking LNG carriers fixed to the project will smash through frozen waters to deliver Arctic cargoes west and eastbound. To do so, the shipowners have made complex new arrangements for lifecycle maintenance, repairs and spares. Mitsui OSK outlines its plans

Mitsui OSK (MOL) has ordered three of the 15 icebreaking 172,000 mᶾ Arc7 LNG carriers that will deliver cargoes from Yamal LNG in the Russian Arctic.

The Japanese shipowner takes delivery of Vladimir Rusanov from Daewoo Shipbuilding & Marine Engineering (DSME) on 31 December, having put the LNG carrier through sea and gas trials off South Korea this autumn. The vessel will undergo ice trials in the Kara Sea before it loads its first cargo in April.

MOL receives its second icebreaker, Vladimir Vice, late next year. It takes delivery of its third, which it has yet to name, by December 2019.

In winter, the three LNG carriers will hammer a course through Arctic waters, sailing westbound from Sabetta to deliver transhipment cargoes to Zeebrugge, Montoir, Dunkerque and Bilbao. But in summer, the vessels have the option to sail eastbound, through the Northern Sea Route, to speed up deliveries to customers in Asia.

The choice of route will depend on Yamal LNG’s annual delivery plans and the terms of its sales and purchase agreements.

Wear and tear

Whichever way they sail, the carriers will endure the harshest waters on earth. Ships sailing east will battle sea ice up to 2.1m thick in summer. In winter, crew will load cargoes at Sabetta in temperatures below -40°C, with added wind chill as the ships set sail for icebound waters.

“It’s an incredibly tough environment,” says MOL LNG Transport (Europe) managing director Andy Hill. “What’s surprised me most from a recent visit to Murmansk, was the impact that ice has on a ship’s hull, in particular.”

Having seen an icebreaker in dry dock, Mr Hill believes hull coatings will be critical to ensure sustainable performance.

“There is so much more to breaking through the ice than straightforward propulsive power,” he says. “Moving through ice creates a lot of vibration. We have to monitor this very, very carefully. We will keep a very close eye on vibration levels and the impact of this on wear and tear.

“The level of winterisation we’ve installed on the exposed decks of our ships exceeds those of icebreaking ships I’ve seen in Murmansk – and so does the level of insulation between outside and inside, which means improved conditions for our seafarers.”

It is critical to predict and minimise the icebreaking LNG carriers’ lifecycle and maintenance costs. MOL has identified its priorities, based on risk analysis, undertaking Hazid and Hazop and carrying out SWOT studies.

To monitor hull, machinery and equipment performance MOL has supplemented its routine reporting with performance-monitoring systems from Kyma. It will capture vibration levels from both fixed and portable sensors.

“Our primary focus has been working with the manufacturers,” Mr Hill says. “Although we have experience with the engines installed on these vessels, we’ve reached agreement for a through-life maintenance contract with Wärtsilä for the engines.”

The deal reassures the customer about reliability. It also makes it easier to predict and manage the supply and maintenance costs. So MOL has concluded several through-life deals with suppliers, working with Cryostar, Honeywell, ABB, Alfa Laval and Atlas Copco to complete the process.

The suppliers agree to provide periodic health checks and will keep technicians on standby, visas in passports, to fly out to troubleshoot.

Team spirit

MOL is one of four shipowners to order the icebreaking LNG carriers that will make up the 15-strong fleet of specialist vessels for the Yamal LNG project. Sovcomflot, Teekay LNG, MOL and Dynagas have set up a steering committee and working groups to look at new technology and to tackle some of the project’s challenges. Yamal LNG and the owners chair the working groups, sharing expertise and responsibilities.

The four owners have worked closely with Yamal LNG. Had Yamal LNG taken the lead, says one observer, “accountability for those costs would have stopped with the charterer, rather than with the shipowner. That would have implied less of a separation between duty and care that the charterer would look for, as the shipowners are the experts.”

MOL believes strongly in reliability, availability and maintainability (RAM) studies. It invited the other owners to participate and agreed a joint focus on the Wärtsilä gas-burning diesel engines.

MOL approached classification society DNV GL, which has a large database of machinery and equipment failures for this study. MOL developed the RAM study to scrutinise every aspect of the ice-class LNG carriers’ machinery, the propulsion systems, power distribution, cargo systems and containment systems. The study helped to identify the required depot spares.

“Experience goes so far,” Mr Hill says. “But we felt there was a need to look separately at the documented data and to have that dialogue with the manufacturers and suppliers – to understand their stock-level process. The DNV GL RAM study has enabled us to do that.”

At the time of writing, the owners were discussing protocols for spares withdrawals if two or more ships report the same failure. They were also negotiating with Yamal LNG owners Novatek and Total over inventory volumes and storage space for spares. Space should become available in Sabetta but it was unclear how much at startup.

“From the point of view of repairs and maintenance, those depot spares will need to be held relatively close to the project,” Mr Hill says. “They’ll be arranged in Europe. However, some of our suppliers with whom we’ve agreed through-life contracts will hold their own spares that we can draw on – but not pay for until we do so – in Europe and in Asia.

“If you need a part, you need to know how long it will take to produce and deliver, particularly now, when the industry is so cautious about having a redundant piece of equipment, but the receiver may reject a ship because the redundant equipment is not fully operational before the vessel loads. That would mean having two engines, duplicate compressors and so forth.

“It’s about having the flexibility to complete the voyage if, for example, you have a repeat failure. That’s one of the main concerns.”

MOL will use condition-based maintenance (CBM) to identify any problems early, and prevent damage to equipment. Being pro-active increases reliability and availability and reduces downtime.

CBM makes it possible to qualify for the classification criteria of condition-based maintenance schemes, avoiding the need for a class surveyor inspection and reducing the overall cost of class surveys.

MOL’s CBM initiative is part of a larger project, taking a fresh approach to managing asset integrity. It uses CBM technologies such as vibration monitoring, thermographic inspection and lube-oil analysis to determine the health of its machinery and equipment.

It has focused in particular on machine-vibration monitoring. “Considering machine repair or replacement costs, loss of production, quality problems, environmental impact and other negative effects of deteriorating machine condition, the implementation of vibration monitoring is well justified,” Mr Hill says.

Planning

Like Teekay LNG, MOL plans to drydock its three LNG icebreakers every two and a half years. It will stagger the schedule, working around charterer requirements. That timescale may change, with experience. “It may evolve, depending on the operating profile and the impact that the harsh environment will have on the vessels,” Mr Hill says.

Bureau Veritas and the Russian Register are jointly classing the 15 icebreaking LNG carriers. In the early days of LNG, vessels went to drydock every two and a half years, notes BV managing director Yannis Calogeras. These more frequent surveys make sense as class and owners study how the ships, their equipment and their coatings stand up to harsh weather, he says.

“We need to measure how much pounding the hull coatings take from the ice. We won’t know the full impact on this, or on the other equipment, until the fleet comes into service.”

MOL has also focused on the human element. As a group, MOL gained some ice experience on the Sakhalin LNG project. However, few of its officers had worked in Arctic waters. It decided to base the nine Vladimir Rusanov deck and engineering officers at DSME’s Okpo shipyard, from design stage to final delivery, to get to know every nook and cranny of this new class of LNG carrier.

MOL’s London-based staff and officers on site have supervised factory-acceptance tests and the shipyard inspections. “This is the first time we’ve involved seafarers from the very outset,” Mr Hill says.

MOL also teamed up with the two Dutch heavylift shipowners, BigRoll and Spliethoff, that have delivered the Yamal LNG plant modules from fabrication yards in China, sailing through the Northern Sea Route to Sabetta. MOL’s Rotterdam-based crew managers arranged for the Vladimir Rusanov officers to join the heavylift vessels to learn the essential elements of ice navigation as their counterparts sailed through the Northern Sea Route, with Russian icebreaker owner-operator Rosatomflot's passage-cutting vessels in attendance.

The MOL officers have worked closely with Rosatomflot. The Vladimir Rusanov officers joined one of the company's icebreakers for a tour of the polar regions to learn about icebreaker technology and communications systems and to build relationships with the Russian officers who work there.

“It was particularly valuable for our senior officers to learn about the different ice formations and experience the noise and the vibrations that come with breaking through ice,” Mr Hill says. “It was a revelation to learn how quickly a vessel can become beset by ice. We’ve learned about the importance of impulsive engine movements to maintain way, and how quickly the density and nature of the ice can change.

“A vessel can increase speed very rapidly – or come to almost a complete stop. If the vessels are moving in convoy, often at distances of less than a mile, they can also be moving at different speeds as they encounter different challenges. You have to act very quickly to react, to avoid collisions.”

Distant waters

It is not yet clear how much time the 15 Arc7 LNG icebreakers will spend in convoy; the vessels are designed for independent navigation through the Northern Sea Route. Convoys have advantages and disadvantages. Mr Hill does not expect the vessels to operate formal convoys as standard, outside Ob Bay and River transits, “unless conditions at sea are close to design extremes”.

“Sailing in convoy allows navigation with a certain dispatch speed, creating fuel economy. But how often we proceed in a formal or informal convoy will also depend on the density of traffic,” he says.

When the weather is at its most brutal, the LNG carriers can deploy a Rosatomflot icebreaker escort.

Communications is particularly tricky in the Arctic. MOL decided early on to rework its satellite arrangements, having discovered, based on latitude and sailing course, that the position of masts and funnels could restrict its communications.

“We’ve respecified the satellite domes, making them bigger and adding a second dome to each ship,” Mr Hill says. “This gives us a greater degree of coverage because the satellites are low on the horizon. The proximity of masts and funnels indicated to us an additional challenge to communications, not only from latitude but from the course the vessels are steering.

“All three ships will have two satellite domes and we have contracted NSSL to provide the satellite communications. This two-dome structure will be unique to the MOL Arctic fleet. There’s been a lot of correspondence.”

Iridium will provide the backup system. MOL says it is the most reliable communications provider in the Arctic. However, Iridium has a relatively low data-transfer capability, Mr Hill says – “and this has implications for real-time remote access and full use of CBM techniques”.

Mr Hill says help will be at hand, within 48 hours’ sailing time, at all points. Every section of the Northern Sea Route has dedicated Rosatomflot icebreakers. Many have helipads for emergency airlifts and are fitted out to deliver medical and even dental services.

Russia Inc has thrown its weight behind Novatek’s Arctic LNG ambitions. It is keeping its icebreakers on standby.

The Russian port authority Rosmaport provides escort tugs and pilots at Sabetta and has agreed with MOL to provide ice pilots for the Northern Sea Route transits. At first, at least, two ice pilots will join every LNG carrier that loads at Sabetta, staying on board for the round trip.

Rosmaport pilots are licensed to work in all Russian Arctic ports. Having watched how the pilots work, Mr Hill says his crew are in safe hands. “The way they work – their experience and depth of knowledge – is seriously impressive,” he concludes. “These guys have a sixth sense for ice.